1. Field of the Invention
The subject of the invention is a supply apparatus for color-bearing film with a supply roll to hold unused color-bearing film.
2. Description of Related Art
For proofing color separations in the printing field, the surface of an image-bearing film is made tacky, for example, by exposure of areas on which a color will be applied. The image-bearing film is then brought into contact with a color-bearing film, or "color film" for short, by a laminator. The laminator has a nip formed by two rollers. In this nip, the color film is pressed against the image-bearing film. Beyond the nip, the color film is separated from the image-bearing film. In this manner, the color remains adhered to the previously tacky areas. The process is repeated with the appropriate number of colors, usually four. Thus, the color separation can be inspected visually, particularly whether the resolution is right.
In known laminators, the supply apparatus for color films consists of a series of color film supply rolls suspended before the nip. The ends of the color films hang down and are fastened on each supply roll, for example, by an adhesive strip. To make a color separation, a technician grasps the end of the film of the desired color, pulls a length of it off the supply roll and threads the end into the nip, for example, with the assistance of a stream of air. The image-bearing film is then similarly threaded into the roller nip. The nip is closed and lamination can start. As soon as the image-bearing film has passed through the nip, the nip is re-opened. The used color film is separated from the supply roll, for example, with a knife. The supply roll is rotated in a direction opposite to the unwind direction in order to backwind any remaining excess of color film. The color film adhering to partial areas of the image-bearing film is then pulled away from the image-bearing film. The used color film is waste.
The manipulation of the color films is relatively cumbersome. The repeated back and forth winding of the color films on the supply rolls can result in some color being rubbed off the film, leading to a defective color separation. Finally, handling of the used film is troublesome. The used color film sheets not only occupy a relatively large space as waste, but they are also difficult to recycle. Moreover, some effort and dexterity are required to separate the color film from the image-bearing film.